3i6 DISCOVERY REPORTS 



deeply pigmented, and larger in proportion to the size of the head than in either 

 S. convexa or S. gaudichaudii. The lateral portions of the cephalosome are broad, the 

 posterior margin of the segment measuring 1 1 mm. 



The coxal plates of the first three free thoracic somites (3rd-5th) are separated by 

 distinct sutures ; the plates of the seventh somite extend backwards to about the middle 

 of the terminal segment, but not as far as the bases of the uropoda : they are longer than 

 the corresponding plates in S. convexa. In the male the sternum of each of the third 

 to the seventh thoracic somites bears a small patch of plumose hairs exactly similar to 

 that described for S. convexa. 



In each of the abdominal segments the posterior margin is slightly produced back- 

 wards to form a median dorsal process ; this is largest on the third segment. The pleural 

 plates of the second and third abdominal segments are short, not extending beyond the 

 anterior margin of the terminal segment; those of the second segment are slightly the 

 longer. The terminal segment is ovate in shape, with a very small longitudinal median 

 dorsal keel which disappears posteriorly : the extremity of the segment is rounded and 

 not truncate as shown in Richardson's figure and in this specimen the transverse ridge 

 shown in her figure is absent. 



The antennule is about half the length of the antenna, the latter extending to about 

 the middle of the third free thoracic somite. The flagellum of the antennule consists of 

 twenty-two joints ; the penultimate joint is very short — only about half the length of the 

 terminal one although twice its width : the latter bears four long setae at its distal ex- 

 tremity. The flagellum of the antenna consists of twenty-one joints, of which the two 

 most distal are short (cf. S. convexa) ; the terminal joint bears a group of five setae at its 

 distal extremity. 



The form of the maxillula, maxilla and mandible could not be made out in this 

 specimen. The basipodite of the maxilliped is separated by a suture from the lamella, 

 and the terminal joint of the palp is small, as it is also in S. convexa and S. gaudichaudii. 

 It is probable that in this species, as in S. convexa and S. gaudichaudii, there is a sexual 

 diff"erence in the form of the spines on the propodus of the second thoracic appendage, 

 for in the male the two types of modified spines are almost exactly similar, though 

 smaller, to those found on the propodus of the males of the above species (see Fig. 14c). 

 As in the allied species, a tuft of plumose setae occurs on the carpus. 



The third thoracic appendage of the male is more delicate than the second, and the 

 propodus bears on its inner margin two rows of spines, six in each row. Each spine has 

 a truncate extremity on which are situated a number of short hairs. The last thoracic 

 appendage has the posterior margin of the propodus, carpus, merus and anterior half 

 of the ischium fringed with long plumose setae : the remaining appendages are furnished 

 with setae which are either simple or serrated. 



The protopodite of each of the first three pairs of pleopods is triangular in shape, the 

 produced angle bearing three plumose setae in the first of these appendages and two in 

 the others. The suture of the fourth pleopod is almost transverse, and the endopod has a 

 rounded extremity. The uropoda extend to near the tip of the terminal segment ; the 



